Revert "Eliminate support for Dart 1 (flutter#5504)" (flutter#5505)

Broke runtime_unittests, which are still running directly from source.

This reverts commit 0ea93c3.

common/settings.cc

@@ -11,6 +11,7 @@ namespace blink {
 std::string Settings::ToString() const {
   std::stringstream stream;
   stream << "Settings: " << std::endl;
+  stream << "script_snapshot_path: " << script_snapshot_path << std::endl;
   stream << "vm_snapshot_data_path: " << vm_snapshot_data_path << std::endl;
   stream << "vm_snapshot_instr_path: " << vm_snapshot_instr_path << std::endl;
   stream << "isolate_snapshot_data_path: " << isolate_snapshot_data_path
@@ -31,6 +32,7 @@ std::string Settings::ToString() const {
   stream << "trace_startup: " << trace_startup << std::endl;
   stream << "endless_trace_buffer: " << endless_trace_buffer << std::endl;
   stream << "enable_dart_profiling: " << enable_dart_profiling << std::endl;
+  stream << "dart_non_checked_mode: " << dart_non_checked_mode << std::endl;
   stream << "enable_observatory: " << enable_observatory << std::endl;
   stream << "observatory_port: " << observatory_port << std::endl;
   stream << "ipv6: " << ipv6 << std::endl;

common/settings.h

@@ -23,6 +23,7 @@ using TaskObserverRemove = std::function<void(intptr_t /* key */)>;
 
 struct Settings {
   // VM settings
+  std::string script_snapshot_path;
   std::string platform_kernel_path;
 
   std::string vm_snapshot_data_path;
@@ -46,6 +47,7 @@ struct Settings {
   bool trace_startup = false;
   bool endless_trace_buffer = false;
   bool enable_dart_profiling = false;
+  bool dart_non_checked_mode = false;
   // Used as the script URI in debug messages. Does not affect how the Dart code
   // is executed.
   std::string advisory_script_uri = "main.dart";

runtime/dart_isolate.cc

@@ -277,9 +277,18 @@ bool DartIsolate::PrepareForRunningFromPrecompiledCode() {
   return true;
 }
 
+static bool LoadScriptSnapshot(std::shared_ptr<const fml::Mapping> mapping,
+                               bool last_piece) {
+  FXL_CHECK(last_piece) << "Script snapshots cannot be divided";
+  if (tonic::LogIfError(Dart_LoadScriptFromSnapshot(mapping->GetMapping(),
+                                                    mapping->GetSize()))) {
+    return false;
+  }
+  return true;
+}
+
 static bool LoadKernelSnapshot(std::shared_ptr<const fml::Mapping> mapping,
                                bool last_piece) {
-  FXL_DCHECK(Dart_IsKernel(mapping->GetMapping(), mapping->GetSize())) << "Only kernel snapshots are supported";
   Dart_Handle library =
       Dart_LoadLibraryFromKernel(mapping->GetMapping(), mapping->GetSize());
   if (tonic::LogIfError(library)) {
@@ -298,6 +307,16 @@ static bool LoadKernelSnapshot(std::shared_ptr<const fml::Mapping> mapping,
   return true;
 }
 
+static bool LoadSnapshot(std::shared_ptr<const fml::Mapping> mapping,
+                         bool last_piece) {
+  if (Dart_IsKernel(mapping->GetMapping(), mapping->GetSize())) {
+    return LoadKernelSnapshot(std::move(mapping), last_piece);
+  } else {
+    return LoadScriptSnapshot(std::move(mapping), last_piece);
+  }
+  return false;
+}
+
 FXL_WARN_UNUSED_RESULT
 bool DartIsolate::PrepareForRunningFromSnapshot(
     std::shared_ptr<const fml::Mapping> mapping,
@@ -321,7 +340,7 @@ bool DartIsolate::PrepareForRunningFromSnapshot(
     return false;
   }
 
-  if (!LoadKernelSnapshot(mapping, last_piece)) {
+  if (!LoadSnapshot(mapping, last_piece)) {
     return false;
   }
 
@@ -547,12 +566,20 @@ Dart_Isolate DartIsolate::DartCreateAndStartServiceIsolate(
   // thread.
   service_isolate->ResetWeakPtrFactory();
 
+  const bool isolate_snapshot_is_dart_2 = Dart_IsDart2Snapshot(
+      vm->GetIsolateSnapshot()->GetData()->GetSnapshotPointer());
+  const bool is_preview_dart2 =
+      (vm->GetPlatformKernel().GetSize() > 0) || isolate_snapshot_is_dart_2;
+  const bool running_from_sources =
+      !DartVM::IsRunningPrecompiledCode() && !is_preview_dart2;
+
   tonic::DartState::Scope scope(service_isolate);
   if (!DartServiceIsolate::Startup(
           settings.ipv6 ? "::1" : "127.0.0.1",  // server IP address
           settings.observatory_port,            // server observatory port
           tonic::DartState::HandleLibraryTag,   // embedder library tag handler
-          false,  // disable websocket origin check
+          running_from_sources,                 // running from source code
+          false,  //  disable websocket origin check
           error   // error (out)
           )) {
     // Error is populated by call to startup.

runtime/dart_service_isolate.cc

@@ -27,6 +27,7 @@
   }
 
 #define kLibrarySourceNamePrefix "/vmservice"
+static const char* kServiceIsolateScript = "vmservice_io.dart";
 
 namespace flutter {
 namespace runtime {
@@ -83,6 +84,7 @@ void DartServiceIsolate::Shutdown(Dart_NativeArguments args) {
 bool DartServiceIsolate::Startup(std::string server_ip,
                                  intptr_t server_port,
                                  Dart_LibraryTagHandler embedder_tag_handler,
+                                 bool running_from_sources,
                                  bool disable_origin_check,
                                  char** error) {
   Dart_Isolate isolate = Dart_CurrentIsolate();
@@ -106,14 +108,31 @@ bool DartServiceIsolate::Startup(std::string server_ip,
         &flutter::runtime::__flutter_embedded_service_isolate_resources_[0]);
   }
 
-  // Set the root library for the isolate.
-  Dart_Handle uri = Dart_NewStringFromCString("dart:vmservice_io");
-  Dart_Handle library = Dart_LookupLibrary(uri);
-  SHUTDOWN_ON_ERROR(library);
-  Dart_Handle result = Dart_SetRootLibrary(library);
-  SHUTDOWN_ON_ERROR(result);
-  result = Dart_SetNativeResolver(library, GetNativeFunction, GetSymbol);
-  SHUTDOWN_ON_ERROR(result);
+  Dart_Handle result;
+
+  if (running_from_sources) {
+    // Use our own library tag handler when loading service isolate sources.
+    Dart_SetLibraryTagHandler(DartServiceIsolate::LibraryTagHandler);
+    // Load main script.
+    Dart_Handle library = LoadScript(kServiceIsolateScript);
+    FXL_DCHECK(library != Dart_Null());
+    SHUTDOWN_ON_ERROR(library);
+    // Setup native entry resolution.
+    result = Dart_SetNativeResolver(library, GetNativeFunction, GetSymbol);
+
+    SHUTDOWN_ON_ERROR(result);
+    // Finalize loading.
+    result = Dart_FinalizeLoading(false);
+    SHUTDOWN_ON_ERROR(result);
+  } else {
+    Dart_Handle uri = Dart_NewStringFromCString("dart:vmservice_io");
+    Dart_Handle library = Dart_LookupLibrary(uri);
+    SHUTDOWN_ON_ERROR(library);
+    result = Dart_SetRootLibrary(library);
+    SHUTDOWN_ON_ERROR(result);
+    result = Dart_SetNativeResolver(library, GetNativeFunction, GetSymbol);
+    SHUTDOWN_ON_ERROR(result);
+  }
 
   // Make runnable.
   Dart_ExitScope();
@@ -127,7 +146,7 @@ bool DartServiceIsolate::Startup(std::string server_ip,
   Dart_EnterIsolate(isolate);
   Dart_EnterScope();
 
-  library = Dart_RootLibrary();
+  Dart_Handle library = Dart_RootLibrary();
   SHUTDOWN_ON_ERROR(library);
 
   // Set the HTTP server's ip.
@@ -155,6 +174,30 @@ bool DartServiceIsolate::Startup(std::string server_ip,
   return true;
 }
 
+Dart_Handle DartServiceIsolate::GetSource(const char* name) {
+  const intptr_t kBufferSize = 512;
+  char buffer[kBufferSize];
+  snprintf(&buffer[0], kBufferSize - 1, "%s/%s", kLibrarySourceNamePrefix,
+           name);
+  const char* vmservice_source = NULL;
+  int r = g_resources->ResourceLookup(buffer, &vmservice_source);
+  FXL_DCHECK(r != EmbedderResources::kNoSuchInstance);
+  return Dart_NewStringFromCString(vmservice_source);
+}
+
+Dart_Handle DartServiceIsolate::LoadScript(const char* name) {
+  Dart_Handle url = Dart_NewStringFromCString("dart:vmservice_io");
+  Dart_Handle source = GetSource(name);
+  return Dart_LoadScript(url, Dart_Null(), source, 0, 0);
+}
+
+Dart_Handle DartServiceIsolate::LoadSource(Dart_Handle library,
+                                           const char* name) {
+  Dart_Handle url = Dart_NewStringFromCString(name);
+  Dart_Handle source = GetSource(name);
+  return Dart_LoadSource(library, url, Dart_Null(), source, 0, 0);
+}
+
 Dart_Handle DartServiceIsolate::LoadResource(Dart_Handle library,
                                              const char* resource_name) {
   // Prepare for invoke call.
@@ -205,4 +248,41 @@ Dart_Handle DartServiceIsolate::LoadResources(Dart_Handle library) {
   return result;
 }
 
+Dart_Handle DartServiceIsolate::LibraryTagHandler(Dart_LibraryTag tag,
+                                                  Dart_Handle library,
+                                                  Dart_Handle url) {
+  if (!Dart_IsLibrary(library)) {
+    return Dart_NewApiError("not a library");
+  }
+  if (!Dart_IsString(url)) {
+    return Dart_NewApiError("url is not a string");
+  }
+  const char* url_string = NULL;
+  Dart_Handle result = Dart_StringToCString(url, &url_string);
+  if (Dart_IsError(result)) {
+    return result;
+  }
+  Dart_Handle library_url = Dart_LibraryUrl(library);
+  const char* library_url_string = NULL;
+  result = Dart_StringToCString(library_url, &library_url_string);
+  if (Dart_IsError(result)) {
+    return result;
+  }
+  if (tag == Dart_kImportTag) {
+    // Embedder handles all requests for external libraries.
+    return g_embedder_tag_handler(tag, library, url);
+  }
+  FXL_DCHECK((tag == Dart_kSourceTag) || (tag == Dart_kCanonicalizeUrl));
+  if (tag == Dart_kCanonicalizeUrl) {
+    // url is already canonicalized.
+    return url;
+  }
+  // Get source from builtin resources.
+  Dart_Handle source = GetSource(url_string);
+  if (Dart_IsError(source)) {
+    return source;
+  }
+  return Dart_LoadSource(library, url, Dart_Null(), source, 0, 0);
+}
+
 }  // namespace blink

runtime/dart_service_isolate.h

@@ -16,6 +16,7 @@ class DartServiceIsolate {
   static bool Startup(std::string server_ip,
                       intptr_t server_port,
                       Dart_LibraryTagHandler embedder_tag_handler,
+                      bool running_from_sources,
                       bool disable_origin_check,
                       char** error);
 
@@ -27,6 +28,14 @@ class DartServiceIsolate {
   static void NotifyServerState(Dart_NativeArguments args);
   static void Shutdown(Dart_NativeArguments args);
 
+  // Script loading.
+  static Dart_Handle GetSource(const char* name);
+  static Dart_Handle LoadScript(const char* name);
+  static Dart_Handle LoadSource(Dart_Handle library, const char* name);
+  static Dart_Handle LibraryTagHandler(Dart_LibraryTag tag,
+                                       Dart_Handle library,
+                                       Dart_Handle url);
+
   // Observatory resource loading.
   static Dart_Handle LoadResources(Dart_Handle library);
   static Dart_Handle LoadResource(Dart_Handle library, const char* name);

runtime/dart_vm.cc

@@ -83,6 +83,14 @@ static const char* kDartAssertArgs[] = {
     // clang-format on
 };
 
+static const char* kDartCheckedModeArgs[] = {
+    // clang-format off
+    "--enable_type_checks",
+    "--error_on_bad_type",
+    "--error_on_bad_override",
+    // clang-format on
+};
+
 static const char* kDartStrongModeArgs[] = {
     // clang-format off
     "--strong",
@@ -316,18 +324,18 @@ DartVM::DartVM(const Settings& settings,
                 arraysize(kDartPrecompilationArgs));
   }
 
-  // Enable asserts if we are not running precompiled code. We run non-
+  // Enable checked mode if we are not running precompiled code. We run non-
   // precompiled code only in the debug product mode.
-  bool enable_asserts = true;
+  bool use_checked_mode = !settings.dart_non_checked_mode;
 
 #if FLUTTER_RUNTIME_MODE == FLUTTER_RUNTIME_MODE_DYNAMIC_PROFILE || \
     FLUTTER_RUNTIME_MODE == FLUTTER_RUNTIME_MODE_DYNAMIC_RELEASE
-  enable_asserts = false;
+  use_checked_mode = false;
 #endif
 
 #if !OS_FUCHSIA
   if (IsRunningPrecompiledCode()) {
-    enable_asserts = false;
+    use_checked_mode = false;
   }
 #endif  // !OS_FUCHSIA
 
@@ -338,12 +346,29 @@ DartVM::DartVM(const Settings& settings,
               arraysize(kDartWriteProtectCodeArgs));
 #endif
 
-  // Require Dart 2.
-  FML_DCHECK(platform_kernel_mapping_->GetSize() > 0);
+  const bool isolate_snapshot_is_dart_2 =
+      Dart_IsDart2Snapshot(isolate_snapshot_->GetData()->GetSnapshotPointer());
 
-  PushBackAll(&args, kDartStrongModeArgs, arraysize(kDartStrongModeArgs));
-  if (enable_asserts) {
+  const bool is_preview_dart2 =
+      (platform_kernel_mapping_->GetSize() > 0) || isolate_snapshot_is_dart_2;
+
+  FXL_DLOG(INFO) << "Dart 2 " << (is_preview_dart2 ? "is" : "is NOT")
+                 << " enabled. Platform kernel: "
+                 << static_cast<bool>(platform_kernel_mapping_->GetSize() > 0)
+                 << " Isolate Snapshot is Dart 2: "
+                 << isolate_snapshot_is_dart_2;
+
+  if (is_preview_dart2) {
+    PushBackAll(&args, kDartStrongModeArgs, arraysize(kDartStrongModeArgs));
+    if (use_checked_mode) {
+      PushBackAll(&args, kDartAssertArgs, arraysize(kDartAssertArgs));
+    }
+  } else if (use_checked_mode) {
+    FXL_DLOG(INFO) << "Checked mode is ON";
     PushBackAll(&args, kDartAssertArgs, arraysize(kDartAssertArgs));
+    PushBackAll(&args, kDartCheckedModeArgs, arraysize(kDartCheckedModeArgs));
+  } else {
+    FXL_DLOG(INFO) << "Is not Dart 2 and Checked mode is OFF";
   }
 
   if (settings.start_paused) {
@@ -365,7 +390,6 @@ DartVM::DartVM(const Settings& settings,
   PushBackAll(&args, kDartFuchsiaTraceArgs, arraysize(kDartFuchsiaTraceArgs));
 #endif
 
-  // Add VM dart_flags last to allow user overrides.
   for (size_t i = 0; i < settings.dart_flags.size(); i++)
     args.push_back(settings.dart_flags[i].c_str());
 

shell/common/isolate_configuration.cc

@@ -145,6 +145,17 @@ std::unique_ptr<IsolateConfiguration> IsolateConfiguration::InferFromSettings(
     }
   }
 
+  // Running from script snapshot.
+  {
+    // TODO(engine): Add AssetManager::GetAsMapping or such to avoid the copy.
+    std::vector<uint8_t> script_snapshot;
+    if (asset_manager && asset_manager->GetAsBuffer(
+                             settings.script_snapshot_path, &script_snapshot)) {
+      return CreateForSnapshot(
+          std::make_unique<fml::DataMapping>(std::move(script_snapshot)));
+    }
+  }
+
   // Running from kernel divided into several pieces (for sharing).
   {
     // TODO(fuchsia): Add AssetManager::GetAsMapping or such to avoid the copy.

shell/common/switches.cc

@@ -129,6 +129,10 @@ blink::Settings SettingsFromCommandLine(const fxl::CommandLine& command_line) {
     }
   }
 
+  // Checked mode overrides.
+  settings.dart_non_checked_mode =
+      command_line.HasOption(FlagForSwitch(Switch::DartNonCheckedMode));
+
   settings.ipv6 = command_line.HasOption(FlagForSwitch(Switch::IPv6));
 
   settings.start_paused =
@@ -157,6 +161,9 @@ blink::Settings SettingsFromCommandLine(const fxl::CommandLine& command_line) {
   command_line.GetOptionValue(FlagForSwitch(Switch::FlutterAssetsDir),
                               &settings.assets_path);
 
+  command_line.GetOptionValue(FlagForSwitch(Switch::Snapshot),
+                              &settings.script_snapshot_path);
+
   command_line.GetOptionValue(FlagForSwitch(Switch::MainDartFile),
                               &settings.main_dart_file_path);